<!DOCTYPE html>
<html>
<head>
  <title>Bootstrap 实例 - 输入框组的大小</title>
  <link href="http://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css" rel="stylesheet">
  <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
  <script src="http://libs.baidu.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
</head>
<body>

<div style="padding: 100px 100px 10px;">
  <form class="bs-example bs-example-form" role="form">
    <div class="input-group input-group-lg">
      <span class="input-group-addon">@</span>
      <input type="text" class="form-control" placeholder="Twitterhandle">
    </div><br>

    <div class="input-group">
      <span class="input-group-addon">@</span>
      <input type="text" class="form-control" placeholder="Twitterhandle">
    </div><br>

    <div class="input-group input-group-sm">
      <span class="input-group-addon">@</span>
      <input type="text" class="form-control" placeholder="Twitterhandle">
    </div>
  </form>
</div>


</body>
</html>